NMR study of the state of water in gelatin

A study was made of the state of water in a rigid chain gelatin matrix in the vapour pressure range of 0 to 0·9 using results of the second moment of the NMR adsorption line and measuring nuclear transverse relaxation times. It was shown that the entire water adsorbed by gelatin over the moisture range examined is combined. The mobility of adsorbed water molecules is lower by 3–5 orders of magnitude than the mobility of free water which is evidence of the existence of strong interaction between water molecules and gelatin macromolecules. Conventional boundaries of regions of gelatin moisture content characterized by centres of water adsorption and the degree of inhibition were established. It was shown that local types of motion in the gelatin itself are released in stages by the action of the water absorbed.